German Chancellor Angela Merkel, center, on Monday walked through the Bornholmer Bridge with people who crossed it first, twenty years ago.Credit
Fabrizio Bensch/Reuters

BERLIN — Chancellor Angela Merkel led a gathering of world leaders in Germany’s capital Monday for a celebration of the night 20 years earlier when the Berlin Wall fell.

Prime Minister Gordon Brown of Britain, President Nicolas Sarkozy of France and President Dmitri A. Medvedev of Russia, as well as Secretary of State Hillary Rodham Clinton, made a ceremonial procession with Mrs. Merkel through the Brandenburg Gate, which for decades stood in the no man’s land between East and West Berlin.

The anniversary has provided Germans and people around the once-divided continent with an opportunity to reflect upon the successful reunification of Germany and the once-unthinkable integration of countries from the former Warsaw Pact into NATO and the European Union.

“It is also possible to overcome the barriers of our own time, just as we succeeded in bringing this about in this divided city in 1989,” Mrs. Merkel told the crowd that had assembled in rain to mark the anniversary of the fall of the wall on Nov. 9, 1989, calling it “a day of celebration for all of Europe.”

To the disappointment of German leaders, President Obama did not attend but made a video statement, introduced by Mrs. Clinton. “Let us never forget Nov. 9, 1989, nor the sacrifices that made it possible,” Mr. Obama said. He added that “there could be no clearer rebuke of tyranny, there could be no stronger affirmation of freedom,” than the sight of people tearing down the wall.

The event swung from festive, with appearances by the tenor Plácido Domingo and the rock band Bon Jovi, to the mournful, as when Mrs. Merkel pointed out the importance of recalling that Nov. 9 was also the date in 1938 of the Nazi-led attacks on Jewish people, businesses and places of worship known as Kristallnacht.

A long line of 1,000 oversize dominoes were toppled along the route of the wall as a symbol of its collapse in the heady days of 1989 when dictatorships tumbled across Eastern Europe.

Lech Walesa, the former shipyard worker who led the fight against Moscow-backed Communism in Poland, pushed over the first domino, reflecting Poland’s leading role in Eastern Europe’s campaign against Communism.

Earlier in the day, Mrs. Merkel walked across the Bornholmer Street bridge, accompanied by Mr. Walesa, who later became president of Poland, and Mikhail S. Gorbachev, the last leader of the Soviet Union. In so doing they retraced the steps of the first East Germans, herself included, surging to West Berlin 20 years ago.

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It was at the Bornholmer Street crossing point that East Berliners peacefully ended the division of their city. Crowds swelled the former checkpoint after an East German official announced that, with immediate effect, travel restrictions would be eased. Rather than use violence to force the masses of people back, the guards opened the gate.

In the crowd on Monday, Lothar Binder, 72, a retired train driver, recalled walking across the bridge in the early morning after the checkpoint opened to join a huge party of Germans celebrating the moment on the Kurfürstendamm, in the west of the city.

On Monday, he said he planned to repeat that same walk “just to remember, to walk and to look around and to see how things changed.” Before that day, Mr. Binder said, he had made his last trip to the western part of the city in 1961 as the wall began to take shape. “I think it is wonderful that things turned out the way they did,” he said.

Jens Pepper, 45, an art critic, remembered seeing the first little East German Trabants driving into West Berlin in the early hours of Nov. 10.

“It was clear that in this moment world history was being written, and that something irreversible was happening,” said Mr. Pepper, who has since moved eastward and now lives a short walk from the former Bornholmer checkpoint in the former East Berlin neighborhood of Prenzlauerberg.

More than 1,000 people lined the bridge Monday night under gray skies and a steady drizzle to hear the chancellor speak, but their loudest cheers came when she thanked Mr. Gorbachev for the reforming attitude he brought to the Soviet leadership that helped make the events of that historic night possible. “You courageously allowed things to happen, and that was much more than we could have expected,” Mrs. Merkel said to chants of “Gorby! Gorby! Gorby!”

But many Russians remain divided on the closing chapter of the cold war, during which the Soviet empire collapsed, and in particular over the question of whether Western powers have kept their promises in the negotiations that led to the reunification of Germany.

In an interview with the German magazine Der Spiegel, Mr. Medvedev said: “After the disappearance of the Warsaw Pact, we were hoping for a higher degree of integration. But what have we received? None of the things that we were assured, namely that NATO would not expand endlessly eastwards and our interests would be continuously taken into consideration.”

A version of this article appears in print on November 10, 2009, on Page A12 of the New York edition with the headline: Retracing Walk West As 2 Berlins Became One. Order Reprints|Today's Paper|Subscribe